Feed axis device of a machine tool

Abstract

The feed axis device of a machine tool is equipped with first and second planetary gear speed reducers, each of which is obtained from an inner element, outer element, and intermediate elements that are disposed between the two, the elements being disposed so as to be mutually rotatable and combined in series so that one of the three elements is a fixed section, one of the two remaining elements is the input section and the other is the output section. The element that is the input section of the first speed reducer and the element that is the input section of the second speed reducer are connected to a single drive source. The element that is the output section of the first speed reducer and the element that is the output section of the second speed reducer are connected. The feed axis device is provided with an actuator.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a U.S. National Phase patent application of International Patent Application No. PCT / JP2013 / 074897, filed on Sep. 13, 2013, which is hereby incorporated by reference in the present disclosure in its entirety.FIELD OF THE INVENTION[0002]The invention relates to a feed axis device of a machine tool.BACKGROUND OF THE INVENTION[0003]In machine tools for machining a workpiece with a rotating tool, chattering vibrations may be generated by machining, i.e., a process for chipping a workpiece by cutting edges of a rotating tool. Generally, the chattering vibrations are more likely generated when a hard-to-cut material is machined. Chattering vibrations deteriorate the machining accuracy of a workpiece. Chattering vibrations often result from insufficient rigidity of a transmission system due to backlash of gear wheels of a reduction drive used in a feed axis device of a machine tool.[0004]In order to reduce chattering vibratio...

AI Technical Summary

Benefits of technology

[0016]According to the invention, the actuator applies rotary torque to the fixture part of one of the first and second reduction drives so as to increase, for heavy cutting, the rigidity of the first and second reduction drives and the vibration damping capacity frictionally between the surfaces of engaging teeth of the two reduction drives, whereby chattering vibration can be reduced. For light cutting or fast feed, the friction between the surfaces of engaging teeth of the two reduction drives can be reduced by reducing the rotary torque applied to the one of the fixture parts whereby the heat generation is also reduced. Further, coolant flowing through the outer rings of the reduction drives prevents the reduction drives from being seized.

Problems solved by technology

This makes the rotary feed device and the control thereof complex.

The driving device of Patent Literature 2 increases the pressure between the surfaces of the engaging teeth of the two reduction devices in order to remove the backlash, but cannot adjust the pressure.

Therefore, although the device enables a feed axis device of a machine tool to increase the rigidity of the power transmission system for heavy cutting or machining with a large-diameter tool, there is a problem that the heat generation is increased.

On the other hand, although the pressure between the surfaces of the teeth should be reduced to reduce the heat generation, it is not possible to adjust the pressure.

Further, for a machining condition under which chattering vibrations are likely generated, the feeding speed is decreased in order to reduce the heat generation, and therefore the performance under normal circumstances of the machine tool cannot be exerted.

Images